The invention relates to a screw compressor comprising a housing with a rotor chamber, two screw rotors arranged in the rotor chamber, the screw rotors being mounted in the housing for rotation about their respective axes of rotation and being intermeshingly drivable in order to convey a medium to be compressed from a suction gas inlet of the housing to a pressure gas outlet of the housing and thereby compress the medium to be compressed, a slide movable in the direction of the rotor axes and adjoining the rotor chamber for controlling the capacity via the effective length of the screw rotors, an adjusting device comprising a cylinder to which pressure is applied by a medium and which is formed by a cylinder chamber and a piston coupled with the slide, and a control device associated with the cylinder for controlling in an continuous control mode an inflow and a return flow of the medium provided for actuating the piston.
Such screw compressors are known from the prior art. Herein, in an continuous control mode for controlling the adjusting device a supply line is provided for the pressure cylinder, via which the piston is movable into all conceivable positions either by inflow of the medium actuating the piston or by return flow of the medium actuating the piston.
In order that the control device of such a screw compressor will operate reliably, it is, however, necessary to be able to recognize the position of the piston of the control device so as to be able to reliably operate the screw compressor in the mixed control ranges.
For this reason, in a screw compressor known from the prior art a position recognition is required for the piston and/or the slide, which involves expenditure.